Impact of 3-mm Blalock-Taussig shunt in neonates and infants with a functionally single ventricle.

Functionally single ventricle (f-SV) is susceptible to volume overload. Atrioventricular valve regurgitation (AVVR) tends to develop and ventricular function deteriorates due to excessive pulmonary blood flow following modified Blalock-Taussig shunt (mBTS). On the other hand, a small caliber graft has risks of early obstruction and poor growth of pulmonary vascular beds. We assessed the effect of mBTS with a 3-mm graft to circumvent volume overload in f-SV on achievement of the right heart bypass. Eleven neonates and infants with f-SV at the median age of 24 days underwent mBTS using a 3-mm graft between August 2004 and June 2007. There were no early deaths, but there was one late death. All survivors achieved bidirectional cavopulmonary shunt (BCPS) at 4.2 months after mBTS. Cardiac catheterization demonstrated sufficient growth of the pulmonary artery (pulmonary artery index, 268+/-98 cm(2)/m(2)), low pulmonary vascular resistance (1.4+/-0.9 U.m(2)). The AVVR remained mild or less. Ventricular end-diastolic volume and ejection fraction were 171+/-61% of the normal value and 64+/-6%, respectively. We conclude that a 3-mm mBTS was useful in preventing f-SV from volume overload and was effective for growing good pulmonary vasculature and achieving a right heart bypass.